This invention relates to a method of generating an image and to a device for generating an image.
In desktop computing, it is now common to use more than one display device. Traditionally, a user would have a computer with a single display device attached, but now it is possible to have more than one display device attached to the computer, which increases the usable display area for the worker. For example, International Patent Application Publication WO 2007/020408 discloses a display system which comprises a plurality of display devices, each displaying respectively an image, a data processing device connected to each display device and controlling the image displayed by each display device, and a user interface device connected to the data processing device. Connecting multiple display devices to a computer is a proven method for improving productivity.
The connection of an additional display device to a computer presents a number of problems. In general, most computers will be provided with only one dedicated video output port such as a VGA output connection. One method by which a second display device can be added to a computer is by adding an additional graphics card to the internal components of the computer, which will have an additional graphics output port. The additional graphics card will provide an additional video output which will allow the second display device to be connected to the computer. However, this solution is relatively expensive and is not suitable for many non-technical users of computers, for whom physically correctly adding the additional video card to their computer is a difficult task.
An alternative method of connecting the second display device is to connect the additional display device to a USB socket on the computer, as, in general, all modern computers are provided with multiple USB sockets. This provides a simple connection topology for the user, but requires additional hardware and software to be present, as in general, USB has a bandwidth that makes the provision of a good quality video output a non-trivial task. It is also desirable that any additional hardware between the computer and the display device is kept as simple as possible, in order to keep down the cost of this solution of adding an additional display device. This means that when connecting an additional display device using a limited bandwidth technology such as USB, certain complex tasks can be difficult to achieve. This is particular the case as desktop computers are more frequently being used to output video, for example through websites such as the You Tube® website.